1. Field of the Invention
The present invention relates to a wireless sensor network and, more particularly, to a wireless sensor network having an extended lifetime through balanced energy consumption and to a management method for the same.
2. Description of the Related Art
A wireless sensor network includes sensor nodes having sensors to collect desired information through sensing, and a sink node to send the collected information one or more devices outside the sensor network.
Unlike existing networks for communication, wireless sensor networks aim to collect information at a distance, and are employed in various applications having scientific, medical, military, or commercial uses.
In general, a node in a wireless sensor network has to employ a small-sized battery because of size limitations. The smallness of a sensor node implies some physical constraints, and the battery size is the most serious constraint. Currently, a battery having a size usable in a sensor node cannot supply sufficient energy to the sensor node. To extend the service lifetime of a sensor network, it is necessary to develop a technique that can handle the distribution and use of battery power.
In a sensor network, a data item and/or event sensed by a sensor node is relayed between nodes toward a sink node. Hence, the energy capacity of each node may affect the lifetime of the whole network.
For example, when a node on a critical path receives data from a number of other nodes and forwards the received data to the sink node, the critical path node may experience rapid energy exhaustion and the usable life of critical path node may be shortened in comparison to other nodes. In this case, the entire network may become useless regardless of energy states of other nodes. Hence, to extend the lifetime of a sensor network, it is necessary to manage the sensor network so that all the nodes can evenly consume the available energy.